Drafting machine



May 16, 1933. c. H. LITTLE 1,909,239

' DRAFTING MACHINE Filed Jan. 13, 1927 2 Sheets-Sheet 2 4 Lweutow:

161% fia m 3 Patented May 16, 1933 PATENT OFFICE I CHARLES H. LITTLE, OFCLEVELAND HEIGHTS, OHIO DRAFTING MACHINE Application filed January 13,1927. Serial No. 160,840.

This invention relates to drafting machines and particularly of thewell-known.

Universal type such as illustrated in numerous prior patents granted tome, among which might be mentioned No. 1,003,765 of September 19, 1911.This type of machine, as is well-known, has a parallel motion mechanismin the form of a jointed arm composed of two parallelograms, the end ofone being adapted to be attached to an anchor either fixed to thedrawing board or movable thereon, and the free end of the other carryinga protractor plate with a revoluble part circularly or angularlyadjustable and having provision for receiving rulers disposed at rightangles to each other. However, certain features of my invention are notconfined to a machine having parallel motion mechanism of the specificform mentioned above.

The principal object of the invention is to provide certain improvementswhich simplify and reduce the cost of construction, increase the utilityof the machine, and

render certain parts more compact and rigid thus increasing the accuracyand durability of the machine.

The invention comprises numerous improvements in the protractor end ofthe machine, these improvements permitting the protractor and rotatableruler carrying arm to rest better and more solidly on the board, andbringing about a more compact arrangement and disposition of the chuckswhich a carry the rulers with reference to the axis of rotation of theruler carrying arm relative to the protractor plate.

The invention may be briefly summarized as consisting in certain noveldetails of construction and combinations and arrangements of parts whichwill be described in the specification and set forth in the appendedclaims.

In the accompanying sheets of drawings showing an embodiment of theinvention which operates very effectively, Fig. 1 is a plan view of thedrafting machine applied to a drawing board; Fig. 2 is a side view ofthe protractor end of the machine; Fig.

3 is a central vertical sectional view of the same; Fig. 4 is a top planview of the protractor end of the machine with the handle removed; Fig.5 is a bottom view of the same; Fig. 6 is a fragmentary bottom view withcertain parts removed; and Fig. 56 7 is a detail transverse sectionalview along the line 7-7 of Fig. 4.

Referring now to the drawings, 10 represents the drawing board to whichis applied the drafting machine which in principle 00- is similar tothose illustrated in my prior patents, This machine is attached to theboard through the medium of an anchor designated generally by thereference character 11. A. mid-anchor is herein illusw trated, thisanchor being applied, to the upper part of the board between the topcorners thereof. The drawing machine proper is attached to the outer endof the anchor 11 through the medium of an anchor plate 12 which isadapted to be quickly and detachably connected to the anchor. Pivoted tothis anchor plate are the parallel rods 13 of the upper parallelogram,the

opposite ends of these rods, as well as the corresponding ends of'theparallel rods 14. of the second parallelogram, being pivotally connectedto a common connecting or joint member in the form of an annulus or disk15.

tractor plate to turn about the center thereas p of and provided with ahandle 17 and two chuck arms 18 and 19 arranged at right angles to eachother and having chucks to slidingly receive the chuck plates of a'pairof rulers 20 and 21, these generally consisting of scales or straightedges.

In this case, as is customary with midanchor machines, the axis ofconnection between the anchor plate 12 and the anchor is inclined withreference to the top edge of the board, and the point of attachment ofthe anchor plate to the anchor is removed some distance from the boardwhich, under ordinary circumstances would leave the anchor, at alltimes, projecting a considerable 1 distance beyond .the board. This isundeportion 23 of the anchor from the relatively short-portion 22, butby pivoting or swinging the outer section on the inner section, thedrafting machine may, when desired, be swung back along with the outerportion 23 of the anchor, close to and on an axis parallel to the board,as 'is often desirable but impossible with the ordinary mid-anchor. Whenthe machine is in this position it is preferably supported on the anchorthrough the medum of a special supporting clip not shown.

The inner or base portion 22 of the anchor has two flanged ends whichare attached to the edge of the board and an intermediate outwardlyprojecting part (forming twoshoulders, which are straddled by two cars23a and. to which the part 23 of the anchor is pivoted. One pivot isformed bya pin 24 fixed in and projecting inwardly from one of the ears28a. The other pivot is formed by a screw 25 projecting through theother ear, the inner ends of the pin 24 and of the screw 25 beingpreferably beveled and engaging in beveled openings in the shoulders ofthe base portion 22. The screw 25 may be provided with a lock nut whendesired so that it will be possible not only to pivot one part on theother but also to quickly detach the two parts and to firmlyconnect themtogether and to insure the outer part being restored to the same placeor position it occupied before removal.

One of the ears 23a; is provided with an extension 236 projectingoverone of the flanged ends of the base portion 22 of the anchor so asto limit the upward swinging movement of the outer part 23 relative tothe base part, and a cross bar 230 on the outer anchor member 23 carriesa set screw 26 which is adapted to engage the middle portion of the basemember 22 of the anchor to form an abutment which holds the outer anchormember in its normal extended position and serves also as a clamp tohold them in rigid relation.

The anchor end of the machine embodies numerous novel features whlch aremore fully described and claimed in divisional application Serial No.370,219, filed June 12, 1929.

The pivots for both ends of both pairs of rods 13 and 14, i. e., thepivots at both ends of both parallelograms, are preferably formed byballs, that is, are ball pivots, but asno claim is made herein to thedetails of these joints, it will be sufficient to state that at bothends of the two parallelograms the rods and members to which the rodsare pivoted are held against ball pivots by spring pressure. At theprotractor end, the rods 14 are pivotally connected to the protractorplate 16 or to an extension 16 thereof by the said ball pivots with theparts yieldingly pressed together and held under tension by a springplate 42 overlyin the ends of the rods, the spring pressure ing obtainedby a screw 43 lying centrally between the pivots and passing through thespring plate 42 and into the protractor plate extension 16 the latterconsisting of a plate fastened by screws or otherwise to the lower sideof the protractor plate. This same plate 42 is utilized in obtaining theyieldable pressure necessary to hold in assembled relation the partsforming the pivotal joint between the protractor plate and-the rulercarrying arm, as will be more fully explained presently.

Taking up'now the construction of the protractor and of the rotatablearm carrying thechucks which are adapted to receive the rulers 20 an 21,it will be observed that the chucks, and therefore the points ofattachment of the rulers to the head, are brought much closer to thecenter of the protractor plate or axis of rotation of the arm than in myprior patent previously referred to, thus attaining not only to a markeddegree the feature of compactness but adding considerably to therigidity of the machine, particularly by reducing spring or bending asfor example by pressure applied to the outer end of either ruler.

In the present construction, instead of positioning the chucks outwardlyfrom the protractor and supporting them by a member projecting over theprotractor late to the pivot point at the center thereo chuck 19 isextended inwardly beneath the protractor plate to and referably beyondthe pivot point, and chuc 18 which is at right angles to the former notonly lies in the plane of chuck 19 beneath the plane of the protractorbut is attached to chuck 19 so close to the center of rotation of thehead as to lie partially beneath the protractor.

Both chucks are secured to a common supportin member which is in theform of a flange stamping 45 having a flanged channel-like portion 45ain which is received and secured chuck 19, this portion being disposedradially with'respect to the rotractor and extending inwardly past t ecenter thereof, as clearly illustrated in the drawings. Additionally,this stamping 45 has 'a flanged channel-like portion 45?) which is atright angles to and somewhat shorter than the flanged or channel portion45a,

and this second mentioned channel portion receives and has secured to itchuck 18 with the end of the latter abutting against the edge of chuck19 (note particularly Fig. 5). The rotatable ruler-carrying armincludes, in addition to the lower stamping 45, an: upper su porting orattachin member which is pre erably in the form or a stamping 46 whichoverlies the protractor plate (note particularly Fig. 4). This stampinghas a radially disposed portion directly above the main part of thestamping 45, this portion extending radially inward slightly beyond the'center of the protractor plate and having a punched opening with abeveled seat for the ball-pivot 47 by which the head is pivotallyconnected to the protractor plate. At the center where the protractorplate has a similar seat for the ball pivot, the parts are held togetheron opposite sides of the ball-pivot by an extension 42a of spring plate42 which is pulled down to exert the requisite degree of pressure by ascrew 48 disposed close to the joint.

The upper stamping 46 is somewhat T-' shaped and outwardly of theprotractor plate it has a lateral extension'46a which has a depressedfoot portion resting upon and secured by a screw 49 to the laterallyextending channel portion 45b of the lower stamping 45.

The protractor plate has an open central portion inside of thearc-shaped grad uated peripheral portion and in this opening the lowerand upper stampings are fastened together between the pivot and thegraduated portion of the protractor, the fastening means preferablyincluding overlapping frictionally engaging ears struck from thetwo'stampings, the upper stamping having marginal, downturned ears 46?)which closely engage ears 450 struck up from the body portion of thelower stamping 45. By these en a ing ears inside the graduated portion 0t e protractor plate and by the attachment between. the stampingsoutside of the protractor, the two stampings are firmly secured togetherwithout any liklihood of relative movement between them and making avery substantial arm for supporting the rulers.

The outer extension of the upper stamping 46a carries a spring actuatedlatch 50 having a nose adapted to snap into any one of a series ofnotches 16b which may be either milled or punched in the peripheralportion of the protractor plate, and additionally it carries a rotatableprotractor member 51 having an indicating line 51a adapted to cooperatewith the graduations of the protractor plate, and still further itcarries a clamp similar to that illustrated in my prior patent to holdtheruler carrying arm inany desired position intermediate the positionsdetermined by the notches 167), this clamp consisting of a screw 52 witha slotted head which receives the periphery of the protractor plate 16and having a threaded upstanding stem extending through stamping 46 andengaged by a nut 53.

Above the protractor plate and disposed centrally with respect thereto,the handle 17 previously referred to, is provided, this handle beingsecured to the upperstamping 46 of the ruler carrying arm by a pair ofscrews 54 which extend from beneath (see Fig. 3) through both stampings45 and 46, as well as through chuck 19. These screws serve also totightly bind together the inner portions of the two stampings formingthe ruler carrying arm.

In order that the protractor end of the machine may be firmly andsquarely supported on the drawing board, there is attached to the lowerside of chuck 19, preferably by means of the screws 54, a strip 55 ofsuitable material, preferably wood, the bottom of which is in the sameplane. with the bottom of the rulers 20 and 21 (note Fig. 2) whensupported in the chucks, this member constituting in efi'ect acontinuation or extension of ruler 21.

As the strip 55 rests upon the drawing paper and in fact is the partthrough which the weight of the draftsmans hand is transmitted to thepaper, it is very desirable that it be formed of a material which willhave the least soiling action on the paper. For that reason, woodinstead of metal is employed. formed separately from the chuck 19, thatreason being that it is very important that the bottom of the strip 55and the bottom surfaces of the rulers rest squarely and evenly on thedrawing board or the drawing There is another reason why it is paper andin case there should be a varia- I By this construction not only are therulers brought in much closer to the center of rotation of the rulercarrying arm about the center of the protractor plate, but as therotating arm instead of the protractor plate rests upon the board and infact constitutes the support for the protractor end of the machine, thelower side of the arm formed by the strip 55 and the lower sides of therulers form a more or less unitary widely extending support havingstability and firmness to a far greater degree than heretofore, it beingnoted that the rotatable part is thus stably supported on the boardindependently of the parallel 'ruler mechanism which is not true ofprior constructions wherein the support for the ruler carrying arm hasbeen through the protractor plate or some other non-rotating part. 9

Having thus described my invention, I claim:

1. A. drafting machine comprising a parallel motion mechanism carrying aprotractor plate, and a ruler connected to the protractor plate andadapted to be supported by the drawing board to which the machine isattached independently of the parallel motion mechanism, and connectingmeans comprising a ruler-holding member for supporting the protractorplate on the board,

said member having a board-engaging por-- tion spaced beneath theprotractor plate and extending axially of the ruler.

2. A drafting machine comprising a parallel motion mechanism having aprotractor plate, and a ruler-supporting arm having upper and lowerspaced parts, the upper part only having a pivotal connection with theplate and the lower part forming a board-engaging member beneath theplate.

3. A drafting machine comprising a parallel motion mechanism providedwith a protractor plate, and a ruler-supporting arm rotatably connectedto the plate and having portions extending inwardly one beneath and oneabove the plate, said portions being connected together outside of theperiphery of the plate and also connected together Within the saidperiphery laterally of the center of the plate.

4. A drafting machine comprising a protractor plate, a parallel motionmechanism attached thereto for connecting the same to a drawing board,and a ruler-supporting arm having an upper portion pivotally connectedto the plate at the center thereof and having a lower board-engagingportion extending beneath the protractor plate and below oneparallelogram adapted to be connectedto a drawing board, a protractorplate connected to the free end of the other parallelos gram, and aruler-supporting arm pivotally connected to the protractor plate andcomposed of two stampings, one carrying rulerreceiving chucks at rightangles to each other and extending inwardly beneath the protractorradially thereof, and the second being secured to the first namedstamping and ex tending radially of the protractor over the "same. v

In testimony whereof, I hereunto aflix my signature. v CHARLES LITTLE.

the center thereof and a'handle rigidly secured to said upper portion ofthe arm concentrically with the pivotal connection between the upperpart of the arm and plate.

5. A drafting machine composed'of two' connected parallelograms, thefree end of one parallelogram adapted to be connected to a drawingboard, a protra'ctor plate connected to the free end of the otherparallelogram, and an arm pivotally connected to the protractor plateand comprising a member having two integral flanged portions formingchannels at right angles to each other and achuck member received ineach of said flanged portions.

6. A draftin machine composed of two connected para lelograms, the freeend of one parallelogram adapted to be connected to a drawing board, aprotractor plate connected to the free end of the other parallelo-vgram, and a ruler-supporting arm pivotally connected to the protractorplate and comprising a member having two integral flanged portions atright angles to each

